How to reproduce:

1. Create new 2D Core project
2. Add any 2D Sprite Sheet somewhere in the Project panel (e.g. Assets folder)
3. Select added Sprite Sheet and in Inspector select Sprite Mode : Multiple and click Apply button
4. Click Sprite Editor button > Slice > Slice > Apply
5. In Hierarchy create new object (2D Object > Sprites > Square)
6. Select created object and in top menu open Window > Animation > Animation
7. In Animation window click Create (and save animation)
8. Drag and Drop three sliced sprites into Animation window
9. Try moving added keys left or right
10. Check console for errors

Expected results: No error in console. It should be possible to move key frame left/right.
Actual results: Unable to move key frames in Animation window and multiple errors are thrown in the Console window if trying to do so.

{noformat}
InvalidCastException: Specified cast is not valid.
UnityEditorInternal.AnimationWindowKeyframe.ToKeyframe () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowCurve.ToAnimationCurve () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowUtility.CreateRendererForCurve (UnityEditorInternal.AnimationWindowCurve curve) (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowUtility.GetCurveWrapper (UnityEditorInternal.AnimationWindowCurve curve, UnityEngine.AnimationClip clip) (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditorInternal.AnimationWindowState.get_activeCurveWrappers () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.UpdateCurveEditorData () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.UpdateSelectedKeysToCurveEditor () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
UnityEditor.AnimEditor.SaveCurveEditorKeySelection () (at <dcc76d87233943b9b3b3c6ef6c77cdbf>:0)
{noformat}

Reproducible on: 2022.2.0a13, 2022.2.0a14, 2022.2.0a18, 2022.2.0a19
Not reproducible on: 2022.2.0a12

Notes: Tested on Win11